[SR-Users] ingress timer

[Kelvin Chua]

agreed. the design of the db and queries are all properly tested, with only
milliseconds of query time even for tables as large as millions of rows. i
wanted to implement this only for insurance and was wondering if it's
doable, theoretically speaking.

the timer module is promising although lacks dynamic assignment of
timeouts. what i have in mind is:
  - do a timer_enable() after receiving an INVITE.
  - on timeout, go to rourte[timeout], statelessly send a cancel to
callee(if applicable) and 408 to caller.
  - OR upon getting a 200 OK from the callee's leg, disable the timer.
  - do you think this is worthy of a feature request? something like
timer_enable(timer_id, enable_disable, timeout)

Kelvin Chua


On Thu, Jan 2, 2014 at 2:46 PM, Alex Balashov <abalashov at evaristesys.com>wrote:

> On 01/02/2014 01:39 AM, Kelvin Chua wrote:
>
>  those timers are for INVITES sent by kamailio right? starting from
>> t_relay() of the INVITE
>> what i am looking for is, when i receive an INVITE, i start counting.
>>
>
> TM's timers - and anything else TM does - are reliant on a transaction
> existing.  A transaction is not created until t_relay() is called.
>
>
>  the reason behind is, with all the functions involving several
>> sql_xquery() involved to find out where to send the t_relay(),
>> there will be unforeseen delays which might cause a very high PDD for my
>> callers, i don't want them to wait.
>>
>
> Even if you had such a timer fire, your database query would still block
> the SIP worker thread that's handling the request route.
>
> If you have database calls that could get hung for several hundred
> milliseconds, or even worse, several seconds, the solution to this problem
> is to fix your architecture and your database calls. Bluntly speaking,
> you're doing it wrong. No database calls or other external calls upon which
> Kamailio relies for call processing should be taking long enough to execute
> that PDD concerns are warranted, or that you should need timers to deal
> with them.
>
> -- Alex
>
>
> --
> Alex Balashov - Principal
> Evariste Systems LLC
> 235 E Ponce de Leon Ave
> Suite 106
> Decatur, GA 30030
> United States
> Tel: +1-678-954-0670
> Web: http://www.evaristesys.com/, http://www.alexbalashov.com/
>
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